What question did this study set out to answer?

To assess whether aortic input impedance and external left ventricular power output can be accurately and reproducibly quantified using noninvasive techniques.

September 19, 2026Journal of the American College of CardiologyOpen Access

Noninvasive determination of aortic input impedance and external left ventricular power output: A validation and repeatability study of a new technique

Q: What are the key findings of this study?

Noninvasive measurement of aortic input impedance and left ventricular power output correlated closely with invasive catheterization data (e.g., systemic vascular resistance r=0.91, P<0.001).

Q: What is the clinical evidence from this study?

Study design: Observational. Population: Subjects undergoing cardiac catheterization (n=35). Intervention: Noninvasive measurement using applanation tonometry and Doppler vs. Invasive measurement via cardiac catheterization. Primary outcome: Systemic vascular resistance (dynes.s.cm-5) (r = 0.91, p=<0.001).

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Key result

Noninvasive aortic impedance and LV power output correlate closely with invasive catheterization data.

r = 0.91
P<0.001
n=35

Why the study?

Aortic input impedance and left ventricular power output have only been determined by invasive techniques, and the accuracy of noninvasive assessment needed validation.

Population

18 subjects undergoing cardiac catheterization and 17 subjects for reproducibility assessment

Comparison

Noninvasive measurements vs invasive measurements

Design

Observational validation and repeatability study

Authors

RKRaymond P. KellyBrigham Young University DFDavid FitchettSt. Michael's Hospital

Discussion

Member takes

Implication

May reduce need for invasive catheterization; leaves open larger validation and outcome trials before practice change.

Key Points

To assess whether aortic input impedance and external left ventricular power output can be accurately and reproducibly quantified using noninvasive techniques.
Recorded central aortic pressure waveforms using calibrated carotid applanation tonometry and measured ascending aortic blood flow using pulsed wave Doppler echocardiography.
Validated noninvasive values against invasive cardiac catheterization data in 18 subjects and evaluated between-day repeatability in 17 separate subjects.
Noninvasive pressure and flow measurements strongly correlated with invasive data for systolic pressure (126 ± 28 vs. 127 ± 28 mm Hg, r=0.96, p<0.001) and cardiac output (5.3 ± 1.2 vs. 5.5 ± 1.3 L/min, r=0.98, p<0.001).
Calculated vascular load parameters demonstrated high accuracy, including systemic vascular resistance (1,479 ± 488 vs. 1,502 ± 498 dynes·s·cm⁻⁵, r=0.91, p<0.001) and characteristic impedance (137 ± 52 vs. 136 ± 79 dynes·s·cm⁻⁵, r=0.92, p<0.001).
Left ventricular mean power (1,107 ± 319 vs. 1,144 ± 266 mW, r=0.93, p<0.001) and pulsatile power correlated closely with invasive measures, with repeated noninvasive tests showing coefficients of variation under 9%.

Study Design

Type

Observational (n=35)

PICO

Population

35 subjects, comprising 18 undergoing cardiac catheterization for validation against invasive measurements and 17 for repeatability assessment.

Exposure / Comparator

Noninvasive measurement using applanation tonometry and Doppler vs Invasive measurement via cardiac catheterization

Primary Outcome

Systemic vascular resistance (dynes.s.cm-5) — r = 0.91, p=<0.001

Main Result

Effect estimate: r = 0.91

Absolute Event Rate: 1479% vs 1502%

p-value: p=<0.001

Cite This Study

Kelly et al. (1992) conducted an observational in Subjects undergoing cardiac catheterization (n=35). Noninvasive measurement using applanation tonometry and Doppler vs. Invasive measurement via cardiac catheterization was evaluated on Systemic vascular resistance (dynes.s.cm-5) (r = 0.91, p=<0.001). Noninvasive measurement of aortic input impedance and left ventricular power output correlated closely with invasive catheterization data (e.g., systemic vascular resistance r=0.91, P<0.001).

synapsesocial.com/papers/6aae52d7234a2bad59d2fe66 https://doi.org/10.1016/0735-1097(92)90198-v

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September 19, 2026Journal of the American College of CardiologyOpen Access

Noninvasive determination of aortic input impedance and external left ventricular power output: A validation and repeatability study of a new technique

View Full Paper

Ask AI

Bookmark

Key result

Noninvasive aortic impedance and LV power output correlate closely with invasive catheterization data.

r = 0.91
P<0.001
n=35

Why the study?

Aortic input impedance and left ventricular power output have only been determined by invasive techniques, and the accuracy of noninvasive assessment needed validation.

Population

18 subjects undergoing cardiac catheterization and 17 subjects for reproducibility assessment

Comparison

Noninvasive measurements vs invasive measurements

Design

Observational validation and repeatability study

Authors

RKRaymond P. KellyBrigham Young University DFDavid FitchettSt. Michael's Hospital

Discussion

Member takes

Implication

May reduce need for invasive catheterization; leaves open larger validation and outcome trials before practice change.

Key Points

To assess whether aortic input impedance and external left ventricular power output can be accurately and reproducibly quantified using noninvasive techniques.
Recorded central aortic pressure waveforms using calibrated carotid applanation tonometry and measured ascending aortic blood flow using pulsed wave Doppler echocardiography.
Validated noninvasive values against invasive cardiac catheterization data in 18 subjects and evaluated between-day repeatability in 17 separate subjects.
Noninvasive pressure and flow measurements strongly correlated with invasive data for systolic pressure (126 ± 28 vs. 127 ± 28 mm Hg, r=0.96, p<0.001) and cardiac output (5.3 ± 1.2 vs. 5.5 ± 1.3 L/min, r=0.98, p<0.001).
Calculated vascular load parameters demonstrated high accuracy, including systemic vascular resistance (1,479 ± 488 vs. 1,502 ± 498 dynes·s·cm⁻⁵, r=0.91, p<0.001) and characteristic impedance (137 ± 52 vs. 136 ± 79 dynes·s·cm⁻⁵, r=0.92, p<0.001).
Left ventricular mean power (1,107 ± 319 vs. 1,144 ± 266 mW, r=0.93, p<0.001) and pulsatile power correlated closely with invasive measures, with repeated noninvasive tests showing coefficients of variation under 9%.

Study Design

Type

Observational (n=35)

PICO

Population

35 subjects, comprising 18 undergoing cardiac catheterization for validation against invasive measurements and 17 for repeatability assessment.

Exposure / Comparator

Noninvasive measurement using applanation tonometry and Doppler vs Invasive measurement via cardiac catheterization

Primary Outcome

Systemic vascular resistance (dynes.s.cm-5) — r = 0.91, p=<0.001

Main Result

Effect estimate: r = 0.91

Absolute Event Rate: 1479% vs 1502%

p-value: p=<0.001

Cite This Study

synapsesocial.com/papers/6aae52d7234a2bad59d2fe66 https://doi.org/10.1016/0735-1097(92)90198-v

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